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Make ReactPerf.start() work during reconciliation #7208
Make ReactPerf.start() work during reconciliation #7208
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This looks cleaner even though it is not strictly necessary. We still call them manually for unmounting because it doesn't have a transaction.
@@ -315,10 +315,6 @@ var ReactMount = { | |||
shouldReuseMarkup, | |||
context | |||
) { | |||
if (__DEV__) { |
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See last commit—I replaced most of these blocks with transactions. (I can revert just that commit if you’re not into this.)
lgtm. Do you have a test with the onError behavior? |
Yes, if I remove this behavior |
* Add failing test demonstrating a ReactPerf warning * Make the failing ReactPerf test more precise * Make ReactPerf.start() work during reconciliation * Reorder lifecycle methods for greater clarity * Fix memory leak * Error boundaries should not break ReactPerf * Put onBeginFlush/onEndFlush into transaction wrappers This looks cleaner even though it is not strictly necessary. We still call them manually for unmounting because it doesn't have a transaction. (cherry picked from commit 1a0e3a3)
* Add failing test demonstrating a ReactPerf warning * Make the failing ReactPerf test more precise * Make ReactPerf.start() work during reconciliation * Reorder lifecycle methods for greater clarity * Fix memory leak * Error boundaries should not break ReactPerf * Put onBeginFlush/onEndFlush into transaction wrappers This looks cleaner even though it is not strictly necessary. We still call them manually for unmounting because it doesn't have a transaction.
Currently
ReactPerf.start()
andReactPerf.stop()
calls don’t work correctly during reconciliation.As far as I know this was occasionally the case before 15.x too—they weren’t working reliably.
Generally we advise that people call
ReactPerf
methods from the console but React components for this appears to be a popular pattern so it’s best we support it.I took the failing test from #7191 and built this PR on top of it.
This should fix the problem so people can write “measurer” components like this:
Why didn’t this work before? We used to only start and stop timers while
isProfiling
is true. However this doesn’t work correctly if the user flipsisProfiling
during reconciliation. Then we have mismatchingbegin
/end
timer calls.To fix this, I decided to always measure methods regardless of whether we are in profiling mode. I suppose calls to
performanceNow()
can’t be expensive, can they? And we are only doing this in__DEV__
anyway.The logic is changed so that we don’t record the measurements if
isProfiling
isfalse
. So we just make them and throw them away (without pushing them into the array). This lets us avoid writing the logic to recover fromisProfiling
flipping in the middle of reconciliation.I also changed the host history tool to only record DOM operations while profiling. Previously they were recorded into an array before being discarded at the end of the flush.
Finally, I fixed a few places (ART and error boundaries) where warning assertions weren’t true. They started firing because we now measure regardless of
isProfiling
. This is actually good because it means we’re testing that ReactPerf doesn’t get confused by bad event ordering during our whole test suite.